/* exif-data.c
 *
 * Copyright (c) 2001 Lutz Mueller <lutz@users.sourceforge.net>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA  02110-1301  USA.
 */

#include <config.h>

#include <libexif/exif-mnote-data.h>
#include <libexif/exif-data.h>
#include <libexif/exif-ifd.h>
#include <libexif/exif-mnote-data-priv.h>
#include <libexif/exif-utils.h>
#include <libexif/exif-loader.h>
#include <libexif/exif-log.h>
#include <libexif/i18n.h>
#include <libexif/exif-system.h>


#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#undef JPEG_MARKER_SOI
#define JPEG_MARKER_SOI  0xd8
#undef JPEG_MARKER_APP0
#define JPEG_MARKER_APP0 0xe0
#undef JPEG_MARKER_APP1
#define JPEG_MARKER_APP1 0xe1

static const unsigned char ExifHeader[] = {0x45, 0x78, 0x69, 0x66, 0x00, 0x00};

struct _ExifDataPrivate {
  ExifByteOrder order;

  ExifMnoteData *md;

  ExifLog *log;
  ExifMem *mem;

  unsigned int ref_count;

  /* Temporarily used while loading data */
  unsigned int offset_mnote;

  ExifDataOption options;
  ExifDataType data_type;
};

static void *
exif_data_alloc(ExifData *data, unsigned int i)
{
  void *d;

  if (!data || !i) {
    return NULL;
  }

  d = exif_mem_alloc(data->priv->mem, i);
  if (d) {
    return d;
  }

  EXIF_LOG_NO_MEMORY(data->priv->log, "ExifData", i);
  return NULL;
}

ExifMnoteData *
exif_data_get_mnote_data(ExifData *d)
{
  return (d && d->priv) ? d->priv->md : NULL;
}

ExifData *
exif_data_new(void)
{
  ExifMem *mem = exif_mem_new_default();
  ExifData *d = exif_data_new_mem(mem);

  exif_mem_unref(mem);

  return d;
}

ExifData *
exif_data_new_mem(ExifMem *mem)
{
  ExifData *data;
  unsigned int i;

  if (!mem) {
    return NULL;
  }

  data = exif_mem_alloc(mem, sizeof(ExifData));
  if (!data) {
    return (NULL);
  }
  data->priv = exif_mem_alloc(mem, sizeof(ExifDataPrivate));
  if (!data->priv) {
    exif_mem_free(mem, data);
    return (NULL);
  }
  data->priv->ref_count = 1;

  data->priv->mem = mem;
  exif_mem_ref(mem);

  for (i = 0; i < EXIF_IFD_COUNT; i++) {
    data->ifd[i] = exif_content_new_mem(data->priv->mem);
    if (!data->ifd[i]) {
      exif_data_free(data);
      return (NULL);
    }
    data->ifd[i]->parent = data;
  }

  /* Default options */
#ifndef NO_VERBOSE_TAG_STRINGS
  /*
   * When the tag list is compiled away, setting this option prevents
   * any tags from being loaded
   */
  exif_data_set_option(data, EXIF_DATA_OPTION_IGNORE_UNKNOWN_TAGS);
#endif
  exif_data_set_option(data, EXIF_DATA_OPTION_FOLLOW_SPECIFICATION);

  /* Default data type: none */
  exif_data_set_data_type(data, EXIF_DATA_TYPE_COUNT);

  return (data);
}

ExifData *
exif_data_new_from_data(const unsigned char *data, unsigned int size)
{
  ExifData *edata;

  edata = exif_data_new();
  exif_data_load_data(edata, data, size);
  return (edata);
}

static int
exif_data_load_data_entry(ExifData *data, ExifEntry *entry,
                          const unsigned char *d,
                          unsigned int size, unsigned int offset)
{
  unsigned int s, doff;

  entry->tag        = exif_get_short(d + offset + 0, data->priv->order);
  entry->format     = exif_get_short(d + offset + 2, data->priv->order);
  entry->components = exif_get_long(d + offset + 4, data->priv->order);

  /* FIXME: should use exif_tag_get_name_in_ifd here but entry->parent
   * has not been set yet
   */
  exif_log(data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
           "Loading entry 0x%x ('%s')...", entry->tag,
           exif_tag_get_name(entry->tag));

  /* {0,1,2,4,8} x { 0x00000000 .. 0xffffffff }
   *   -> { 0x000000000 .. 0x7fffffff8 } */
  s = exif_format_get_size(entry->format) * entry->components;
  if ((s < entry->components) || (s == 0)) {
    return 0;
  }

  /*
   * Size? If bigger than 4 bytes, the actual data is not
   * in the entry but somewhere else (offset).
   */
  if (s > 4) {
    doff = exif_get_long(d + offset + 8, data->priv->order);
  } else {
    doff = offset + 8;
  }

  /* Sanity checks */
  if ((doff + s < doff) || (doff + s < s) || (doff + s > size)) {
    exif_log(data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
             "Tag data past end of buffer (%u > %u)", doff + s, size);
    return 0;
  }

  entry->data = exif_data_alloc(data, s);
  if (entry->data) {
    entry->size = s;
    memcpy(entry->data, d + doff, s);
  } else {
    /* FIXME: What do our callers do if (entry->data == NULL)? */
    EXIF_LOG_NO_MEMORY(data->priv->log, "ExifData", s);
  }

  /* If this is the MakerNote, remember the offset */
  if (entry->tag == EXIF_TAG_MAKER_NOTE) {
    if (!entry->data) {
      exif_log(data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
               "MakerNote found with empty data");
    } else if (entry->size > 6) {
      exif_log(data->priv->log,
               EXIF_LOG_CODE_DEBUG, "ExifData",
               "MakerNote found (%02x %02x %02x %02x "
               "%02x %02x %02x...).",
               entry->data[0], entry->data[1], entry->data[2],
               entry->data[3], entry->data[4], entry->data[5],
               entry->data[6]);
    }
    data->priv->offset_mnote = doff;
  }
  return 1;
}

static void
exif_data_save_data_entry(ExifData *data, ExifEntry *e,
                          unsigned char **d, unsigned int *ds,
                          unsigned int offset)
{
  unsigned int doff, s;
  unsigned int ts;

  if (!data || !data->priv) {
    return;
  }

  /*
   * Each entry is 12 bytes long. The memory for the entry has
   * already been allocated.
   */
  exif_set_short(*d + 6 + offset + 0,
                 data->priv->order, (ExifShort) e->tag);
  exif_set_short(*d + 6 + offset + 2,
                 data->priv->order, (ExifShort) e->format);

  if (!(data->priv->options & EXIF_DATA_OPTION_DONT_CHANGE_MAKER_NOTE)) {
    /* If this is the maker note tag, update it. */
    if ((e->tag == EXIF_TAG_MAKER_NOTE) && data->priv->md) {
      /* TODO: this is using the wrong ExifMem to free e->data */
      exif_mem_free(data->priv->mem, e->data);
      e->data = NULL;
      e->size = 0;
      exif_mnote_data_set_offset(data->priv->md, *ds - 6);
      exif_mnote_data_save(data->priv->md, &e->data, &e->size);
      e->components = e->size;
    }
  }

  exif_set_long(*d + 6 + offset + 4,
                data->priv->order, e->components);

  /*
   * Size? If bigger than 4 bytes, the actual data is not in
   * the entry but somewhere else.
   */
  s = exif_format_get_size(e->format) * e->components;
  if (s > 4) {
    unsigned char *t;
    doff = *ds - 6;
    ts = *ds + s;

    /*
     * According to the TIFF specification,
     * the offset must be an even number. If we need to introduce
     * a padding byte, we set it to 0.
     */
    if (s & 1) {
      ts++;
    }
    t = exif_mem_realloc(data->priv->mem, *d, ts);
    if (!t) {
      EXIF_LOG_NO_MEMORY(data->priv->log, "ExifData", ts);
      return;
    }
    *d = t;
    *ds = ts;
    exif_set_long(*d + 6 + offset + 8, data->priv->order, doff);
    if (s & 1) {
      *(*d + *ds - 1) = '\0';
    }

  } else {
    doff = offset + 8;
  }

  /* Write the data. Fill unneeded bytes with 0. Do not crash with
   * e->data is NULL */
  if (e->data) {
    memcpy(*d + 6 + doff, e->data, s);
  } else {
    memset(*d + 6 + doff, 0, s);
  }
  if (s < 4) {
    memset(*d + 6 + doff + s, 0, (4 - s));
  }
}

static void
exif_data_load_data_thumbnail(ExifData *data, const unsigned char *d,
                              unsigned int ds, ExifLong o, ExifLong s)
{
  /* Sanity checks */
  if ((o + s < o) || (o + s < s) || (o + s > ds) || (o > ds)) {
    exif_log(data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
             "Bogus thumbnail offset (%u) or size (%u).",
             o, s);
    return;
  }

  if (data->data) {
    exif_mem_free(data->priv->mem, data->data);
  }
  if (!(data->data = exif_data_alloc(data, s))) {
    EXIF_LOG_NO_MEMORY(data->priv->log, "ExifData", s);
    data->size = 0;
    return;
  }
  data->size = s;
  memcpy(data->data, d + o, s);
}

#undef CHECK_REC
#define CHECK_REC(i)          \
  if ((i) == ifd) {       \
    exif_log (data->priv->log, EXIF_LOG_CODE_DEBUG, \
              "ExifData", "Recursive entry in IFD " \
              "'%s' detected. Skipping...",   \
              exif_ifd_get_name (i));     \
    break;            \
  }             \
  if (data->ifd[(i)]->count) {        \
    exif_log (data->priv->log, EXIF_LOG_CODE_DEBUG, \
              "ExifData", "Attempt to load IFD "  \
              "'%s' multiple times detected. "  \
              "Skipping...",        \
              exif_ifd_get_name (i));     \
    break;            \
  }

/*! Load data for an IFD.
 *
 * \param[in,out] data #ExifData
 * \param[in] ifd IFD to load
 * \param[in] d pointer to buffer containing raw IFD data
 * \param[in] ds size of raw data in buffer at \c d
 * \param[in] offset offset into buffer at \c d at which IFD starts
 * \param[in] recursion_depth number of times this function has been
 * recursively called without returning
 */
static void
exif_data_load_data_content(ExifData *data, ExifIfd ifd,
                            const unsigned char *d,
                            unsigned int ds, unsigned int offset, unsigned int recursion_depth)
{
  ExifLong o, thumbnail_offset = 0, thumbnail_length = 0;
  ExifShort n;
  ExifEntry *entry;
  unsigned int i;
  ExifTag tag;

  if (!data || !data->priv) {
    return;
  }

  /* check for valid ExifIfd enum range */
  if ((((int)ifd) < 0) || (((int)ifd) >= EXIF_IFD_COUNT)) {
    return;
  }

  if (recursion_depth > 30) {
    exif_log(data->priv->log, EXIF_LOG_CODE_CORRUPT_DATA, "ExifData",
             "Deep recursion detected!");
    return;
  }

  /* Read the number of entries */
  if ((offset + 2 < offset) || (offset + 2 < 2) || (offset + 2 > ds)) {
    exif_log(data->priv->log, EXIF_LOG_CODE_CORRUPT_DATA, "ExifData",
             "Tag data past end of buffer (%u > %u)", offset + 2, ds);
    return;
  }
  n = exif_get_short(d + offset, data->priv->order);
  exif_log(data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
           "Loading %hu entries...", n);
  offset += 2;

  /* Check if we have enough data. */
  if (offset + 12 * n > ds) {
    n = (ds - offset) / 12;
    exif_log(data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
             "Short data; only loading %hu entries...", n);
  }

  for (i = 0; i < n; i++) {

    tag = exif_get_short(d + offset + 12 * i, data->priv->order);
    switch (tag) {
      case EXIF_TAG_EXIF_IFD_POINTER:
      case EXIF_TAG_GPS_INFO_IFD_POINTER:
      case EXIF_TAG_INTEROPERABILITY_IFD_POINTER:
      case EXIF_TAG_JPEG_INTERCHANGE_FORMAT_LENGTH:
      case EXIF_TAG_JPEG_INTERCHANGE_FORMAT:
        o = exif_get_long(d + offset + 12 * i + 8,
                          data->priv->order);
        /* FIXME: IFD_POINTER tags aren't marked as being in a
         * specific IFD, so exif_tag_get_name_in_ifd won't work
         */
        exif_log(data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
                 "Sub-IFD entry 0x%x ('%s') at %u.", tag,
                 exif_tag_get_name(tag), o);
        switch (tag) {
          case EXIF_TAG_EXIF_IFD_POINTER:
            CHECK_REC(EXIF_IFD_EXIF);
            exif_data_load_data_content(data, EXIF_IFD_EXIF, d, ds, o, recursion_depth + 1);
            break;
          case EXIF_TAG_GPS_INFO_IFD_POINTER:
            CHECK_REC(EXIF_IFD_GPS);
            exif_data_load_data_content(data, EXIF_IFD_GPS, d, ds, o, recursion_depth + 1);
            break;
          case EXIF_TAG_INTEROPERABILITY_IFD_POINTER:
            CHECK_REC(EXIF_IFD_INTEROPERABILITY);
            exif_data_load_data_content(data, EXIF_IFD_INTEROPERABILITY, d, ds, o, recursion_depth + 1);
            break;
          case EXIF_TAG_JPEG_INTERCHANGE_FORMAT:
            thumbnail_offset = o;
            if (thumbnail_offset && thumbnail_length)
              exif_data_load_data_thumbnail(data, d,
                                            ds, thumbnail_offset,
                                            thumbnail_length);
            break;
          case EXIF_TAG_JPEG_INTERCHANGE_FORMAT_LENGTH:
            thumbnail_length = o;
            if (thumbnail_offset && thumbnail_length)
              exif_data_load_data_thumbnail(data, d,
                                            ds, thumbnail_offset,
                                            thumbnail_length);
            break;
          default:
            return;
        }
        break;
      default:

        /*
         * If we don't know the tag, don't fail. It could be that new
         * versions of the standard have defined additional tags. Note that
         * 0 is a valid tag in the GPS IFD.
         */
        if (!exif_tag_get_name_in_ifd(tag, ifd)) {

          /*
           * Special case: Tag and format 0. That's against specification
           * (at least up to 2.2). But Photoshop writes it anyways.
           */
          if (!memcmp(d + offset + 12 * i, "\0\0\0\0", 4)) {
            exif_log(data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
                     "Skipping empty entry at position %u in '%s'.", i,
                     exif_ifd_get_name(ifd));
            break;
          }
          exif_log(data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
                   "Unknown tag 0x%04x (entry %u in '%s'). Please report this tag "
                   "to <libexif-devel@lists.sourceforge.net>.", tag, i,
                   exif_ifd_get_name(ifd));
          if (data->priv->options & EXIF_DATA_OPTION_IGNORE_UNKNOWN_TAGS) {
            break;
          }
        }
        entry = exif_entry_new_mem(data->priv->mem);
        if (exif_data_load_data_entry(data, entry, d, ds,
                                      offset + 12 * i)) {
          exif_content_add_entry(data->ifd[ifd], entry);
        }
        exif_entry_unref(entry);
        break;
    }
  }
}

static int
cmp_func(const unsigned char *p1, const unsigned char *p2, ExifByteOrder o)
{
  ExifShort tag1 = exif_get_short(p1, o);
  ExifShort tag2 = exif_get_short(p2, o);

  return (tag1 < tag2) ? -1 : (tag1 > tag2) ? 1 : 0;
}

static int
cmp_func_intel(const void *elem1, const void *elem2)
{
  return cmp_func((const unsigned char *) elem1,
                  (const unsigned char *) elem2, EXIF_BYTE_ORDER_INTEL);
}

static int
cmp_func_motorola(const void *elem1, const void *elem2)
{
  return cmp_func((const unsigned char *) elem1,
                  (const unsigned char *) elem2, EXIF_BYTE_ORDER_MOTOROLA);
}

static void
exif_data_save_data_content(ExifData *data, ExifContent *ifd,
                            unsigned char **d, unsigned int *ds,
                            unsigned int offset)
{
  unsigned int j, n_ptr = 0, n_thumb = 0;
  ExifIfd i;
  unsigned char *t;
  unsigned int ts;

  if (!data || !data->priv || !ifd || !d || !ds) {
    return;
  }

  for (i = 0; i < EXIF_IFD_COUNT; i++)
    if (ifd == data->ifd[i]) {
      break;
    }
  if (i == EXIF_IFD_COUNT) {
    return;  /* error */
  }

  /*
   * Check if we need some extra entries for pointers or the thumbnail.
   */
  switch (i) {
    case EXIF_IFD_0:

      /*
       * The pointer to IFD_EXIF is in IFD_0. The pointer to
       * IFD_INTEROPERABILITY is in IFD_EXIF.
       */
      if (data->ifd[EXIF_IFD_EXIF]->count ||
          data->ifd[EXIF_IFD_INTEROPERABILITY]->count) {
        n_ptr++;
      }

      /* The pointer to IFD_GPS is in IFD_0. */
      if (data->ifd[EXIF_IFD_GPS]->count) {
        n_ptr++;
      }

      break;
    case EXIF_IFD_1:
      if (data->size) {
        n_thumb = 2;
      }
      break;
    case EXIF_IFD_EXIF:
      if (data->ifd[EXIF_IFD_INTEROPERABILITY]->count) {
        n_ptr++;
      }
    default:
      break;
  }

  /*
   * Allocate enough memory for all entries
   * and the number of entries.
   */
  ts = *ds + (2 + (ifd->count + n_ptr + n_thumb) * 12 + 4);
  t = exif_mem_realloc(data->priv->mem, *d, ts);
  if (!t) {
    EXIF_LOG_NO_MEMORY(data->priv->log, "ExifData", ts);
    return;
  }
  *d = t;
  *ds = ts;

  /* Save the number of entries */
  exif_set_short(*d + 6 + offset, data->priv->order,
                 (ExifShort)(ifd->count + n_ptr + n_thumb));
  offset += 2;

  /*
   * Save each entry. Make sure that no memcpys from NULL pointers are
   * performed
   */
  exif_log(data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
           "Saving %i entries (IFD '%s', offset: %i)...",
           ifd->count, exif_ifd_get_name(i), offset);
  for (j = 0; j < ifd->count; j++) {
    if (ifd->entries[j]) {
      exif_data_save_data_entry(data, ifd->entries[j], d, ds,
                                offset + 12 * j);
    }
  }

  offset += 12 * ifd->count;

  /* Now save special entries. */
  switch (i) {
    case EXIF_IFD_0:

      /*
       * The pointer to IFD_EXIF is in IFD_0.
       * However, the pointer to IFD_INTEROPERABILITY is in IFD_EXIF,
       * therefore, if IFD_INTEROPERABILITY is not empty, we need
       * IFD_EXIF even if latter is empty.
       */
      if (data->ifd[EXIF_IFD_EXIF]->count ||
          data->ifd[EXIF_IFD_INTEROPERABILITY]->count) {
        exif_set_short(*d + 6 + offset + 0, data->priv->order,
                       EXIF_TAG_EXIF_IFD_POINTER);
        exif_set_short(*d + 6 + offset + 2, data->priv->order,
                       EXIF_FORMAT_LONG);
        exif_set_long(*d + 6 + offset + 4, data->priv->order,
                      1);
        exif_set_long(*d + 6 + offset + 8, data->priv->order,
                      *ds - 6);
        exif_data_save_data_content(data,
                                    data->ifd[EXIF_IFD_EXIF], d, ds, *ds - 6);
        offset += 12;
      }

      /* The pointer to IFD_GPS is in IFD_0, too. */
      if (data->ifd[EXIF_IFD_GPS]->count) {
        exif_set_short(*d + 6 + offset + 0, data->priv->order,
                       EXIF_TAG_GPS_INFO_IFD_POINTER);
        exif_set_short(*d + 6 + offset + 2, data->priv->order,
                       EXIF_FORMAT_LONG);
        exif_set_long(*d + 6 + offset + 4, data->priv->order,
                      1);
        exif_set_long(*d + 6 + offset + 8, data->priv->order,
                      *ds - 6);
        exif_data_save_data_content(data,
                                    data->ifd[EXIF_IFD_GPS], d, ds, *ds - 6);
        offset += 12;
      }

      break;
    case EXIF_IFD_EXIF:

      /*
       * The pointer to IFD_INTEROPERABILITY is in IFD_EXIF.
       * See note above.
       */
      if (data->ifd[EXIF_IFD_INTEROPERABILITY]->count) {
        exif_set_short(*d + 6 + offset + 0, data->priv->order,
                       EXIF_TAG_INTEROPERABILITY_IFD_POINTER);
        exif_set_short(*d + 6 + offset + 2, data->priv->order,
                       EXIF_FORMAT_LONG);
        exif_set_long(*d + 6 + offset + 4, data->priv->order,
                      1);
        exif_set_long(*d + 6 + offset + 8, data->priv->order,
                      *ds - 6);
        exif_data_save_data_content(data,
                                    data->ifd[EXIF_IFD_INTEROPERABILITY], d, ds,
                                    *ds - 6);
        offset += 12;
      }

      break;
    case EXIF_IFD_1:

      /*
       * Information about the thumbnail (if any) is saved in
       * IFD_1.
       */
      if (data->size) {

        /* EXIF_TAG_JPEG_INTERCHANGE_FORMAT */
        exif_set_short(*d + 6 + offset + 0, data->priv->order,
                       EXIF_TAG_JPEG_INTERCHANGE_FORMAT);
        exif_set_short(*d + 6 + offset + 2, data->priv->order,
                       EXIF_FORMAT_LONG);
        exif_set_long(*d + 6 + offset + 4, data->priv->order,
                      1);
        exif_set_long(*d + 6 + offset + 8, data->priv->order,
                      *ds - 6);
        ts = *ds + data->size;
        t = exif_mem_realloc(data->priv->mem, *d, ts);
        if (!t) {
          EXIF_LOG_NO_MEMORY(data->priv->log, "ExifData",
                             ts);
          return;
        }
        *d = t;
        *ds = ts;
        memcpy(*d + *ds - data->size, data->data, data->size);
        offset += 12;

        /* EXIF_TAG_JPEG_INTERCHANGE_FORMAT_LENGTH */
        exif_set_short(*d + 6 + offset + 0, data->priv->order,
                       EXIF_TAG_JPEG_INTERCHANGE_FORMAT_LENGTH);
        exif_set_short(*d + 6 + offset + 2, data->priv->order,
                       EXIF_FORMAT_LONG);
        exif_set_long(*d + 6 + offset + 4, data->priv->order,
                      1);
        exif_set_long(*d + 6 + offset + 8, data->priv->order,
                      data->size);
        offset += 12;
      }

      break;
    default:
      break;
  }

  /* Sort the directory according to TIFF specification */
  qsort(*d + 6 + offset - (ifd->count + n_ptr + n_thumb) * 12,
        (ifd->count + n_ptr + n_thumb), 12,
        (data->priv->order == EXIF_BYTE_ORDER_INTEL) ? cmp_func_intel : cmp_func_motorola);

  /* Correctly terminate the directory */
  if (i == EXIF_IFD_0 && (data->ifd[EXIF_IFD_1]->count ||
                          data->size)) {

    /*
     * We are saving IFD 0. Tell where IFD 1 starts and save
     * IFD 1.
     */
    exif_set_long(*d + 6 + offset, data->priv->order, *ds - 6);
    exif_data_save_data_content(data, data->ifd[EXIF_IFD_1], d, ds,
                                *ds - 6);
  } else {
    exif_set_long(*d + 6 + offset, data->priv->order, 0);
  }
}

typedef enum {
  EXIF_DATA_TYPE_MAKER_NOTE_NONE    = 0,
  EXIF_DATA_TYPE_MAKER_NOTE_CANON   = 1,
  EXIF_DATA_TYPE_MAKER_NOTE_OLYMPUS = 2,
  EXIF_DATA_TYPE_MAKER_NOTE_PENTAX  = 3,
  EXIF_DATA_TYPE_MAKER_NOTE_NIKON   = 4,
  EXIF_DATA_TYPE_MAKER_NOTE_CASIO   = 5,
  EXIF_DATA_TYPE_MAKER_NOTE_FUJI    = 6
} ExifDataTypeMakerNote;

/*! If MakerNote is recognized, load it.
 *
 * \param[in,out] data #ExifData
 * \param[in] d pointer to raw EXIF data
 * \param[in] ds length of data at d
 */
static void
interpret_maker_note(ExifData *data, const unsigned char *d, unsigned int ds)
{
#ifdef USE_ALL_BRANDS
  int mnoteid;
  ExifEntry *e = exif_data_get_entry(data, EXIF_TAG_MAKER_NOTE);
  if (!e) {
    return;
  }

  if ((mnoteid = exif_mnote_data_olympus_identify(data, e)) != 0) {
    exif_log(data->priv->log, EXIF_LOG_CODE_DEBUG,
             "ExifData", "Olympus MakerNote variant type %d", mnoteid);
    data->priv->md = exif_mnote_data_olympus_new(data->priv->mem);

  } else if ((mnoteid = exif_mnote_data_canon_identify(data, e)) != 0) {
    exif_log(data->priv->log, EXIF_LOG_CODE_DEBUG,
             "ExifData", "Canon MakerNote variant type %d", mnoteid);
    data->priv->md = exif_mnote_data_canon_new(data->priv->mem, data->priv->options);

  } else if ((mnoteid = exif_mnote_data_fuji_identify(data, e)) != 0) {
    exif_log(data->priv->log, EXIF_LOG_CODE_DEBUG,
             "ExifData", "Fuji MakerNote variant type %d", mnoteid);
    data->priv->md = exif_mnote_data_fuji_new(data->priv->mem);

    /* NOTE: Must do Pentax detection last because some of the
     * heuristics are pretty general. */
  } else if ((mnoteid = exif_mnote_data_pentax_identify(data, e)) != 0) {
    exif_log(data->priv->log, EXIF_LOG_CODE_DEBUG,
             "ExifData", "Pentax MakerNote variant type %d", mnoteid);
    data->priv->md = exif_mnote_data_pentax_new(data->priv->mem);
  }

  /*
   * If we are able to interpret the maker note, do so.
   */
  if (data->priv->md) {
    exif_mnote_data_log(data->priv->md, data->priv->log);
    exif_mnote_data_set_byte_order(data->priv->md,
                                   data->priv->order);
    exif_mnote_data_set_offset(data->priv->md,
                               data->priv->offset_mnote);
    exif_mnote_data_load(data->priv->md, d, ds);
  }
#endif
}

#define LOG_TOO_SMALL \
  exif_log (data->priv->log, EXIF_LOG_CODE_CORRUPT_DATA, "ExifData", \
            _("Size of data too small to allow for EXIF data."));

void
exif_data_load_data(ExifData *data, const unsigned char *d_orig,
                    unsigned int ds)
{
  unsigned int l;
  ExifLong offset;
  ExifShort n;
  const unsigned char *d = d_orig;
  unsigned int  fullds;

  if (!data || !data->priv || !d || !ds) {
    return;
  }

  exif_log(data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
           "Parsing %i byte(s) EXIF data...\n", ds);

  /*
   * It can be that the data starts with the EXIF header. If it does
   * not, search the EXIF marker.
   */
  if (ds < 6) {
    LOG_TOO_SMALL;
    return;
  }
  if (!memcmp(d, ExifHeader, 6)) {
    exif_log(data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
             "Found EXIF header.");
  } else {
    while (ds >= 3) {
      while (ds && (d[0] == 0xff)) {
        d++;
        ds--;
      }

      /* JPEG_MARKER_SOI */
      if (ds && d[0] == JPEG_MARKER_SOI) {
        d++;
        ds--;
        continue;
      }

      /* JPEG_MARKER_APP0 */
      if (ds >= 3 && d[0] == JPEG_MARKER_APP0) {
        d++;
        ds--;
        l = (d[0] << 8) | d[1];
        if (l > ds) {
          return;
        }
        d += l;
        ds -= l;
        continue;
      }

      /* JPEG_MARKER_APP1 */
      if (ds && d[0] == JPEG_MARKER_APP1) {
        break;
      }

      /* Unknown marker or data. Give up. */
      exif_log(data->priv->log, EXIF_LOG_CODE_CORRUPT_DATA,
               "ExifData", _("EXIF marker not found."));
      return;
    }
    if (ds < 3) {
      LOG_TOO_SMALL;
      return;
    }
    d++;
    ds--;
//    len = (d[0] << 8) | d[1];
//    exif_log(data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
//             "We have to deal with %i byte(s) of EXIF data.",
//             len);
    d += 2;
    ds -= 2;
  }

  /*
   * Verify the exif header
   * (offset 2, length 6).
   */
  if (ds < 6) {
    LOG_TOO_SMALL;
    return;
  }
  if (memcmp(d, ExifHeader, 6)) {
    exif_log(data->priv->log, EXIF_LOG_CODE_CORRUPT_DATA,
             "ExifData", _("EXIF header not found."));
    return;
  }

  exif_log(data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
           "Found EXIF header.");

  /* Sanity check the data length */
  if (ds < 14) {
    return;
  }

  /* The JPEG APP1 section can be no longer than 64 KiB (including a
     16-bit length), so cap the data length to protect against overflow
     in future offset calculations */
  fullds = ds;
  if (ds > 0xfffe) {
    ds = 0xfffe;
  }

  /* Byte order (offset 6, length 2) */
  if (!memcmp(d + 6, "II", 2)) {
    data->priv->order = EXIF_BYTE_ORDER_INTEL;
  } else if (!memcmp(d + 6, "MM", 2)) {
    data->priv->order = EXIF_BYTE_ORDER_MOTOROLA;
  } else {
    exif_log(data->priv->log, EXIF_LOG_CODE_CORRUPT_DATA,
             "ExifData", _("Unknown encoding."));
    return;
  }

  /* Fixed value */
  if (exif_get_short(d + 8, data->priv->order) != 0x002a) {
    return;
  }

  /* IFD 0 offset */
  offset = exif_get_long(d + 10, data->priv->order);
  exif_log(data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
           "IFD 0 at %i.", (int) offset);

  /* Sanity check the offset, being careful about overflow */
  if (offset > ds || offset + 6 + 2 > ds) {
    return;
  }

  /* Parse the actual exif data (usually offset 14 from start) */
  exif_data_load_data_content(data, EXIF_IFD_0, d + 6, ds - 6, offset, 0);

  /* IFD 1 offset */
  n = exif_get_short(d + 6 + offset, data->priv->order);
  if (offset + 6 + 2 + 12 * n + 4 > ds) {
    return;
  }

  offset = exif_get_long(d + 6 + offset + 2 + 12 * n, data->priv->order);
  if (offset) {
    exif_log(data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
             "IFD 1 at %i.", (int) offset);

    /* Sanity check. */
    if (offset > ds || offset + 6 > ds) {
      exif_log(data->priv->log, EXIF_LOG_CODE_CORRUPT_DATA,
               "ExifData", "Bogus offset of IFD1.");
    } else {
      exif_data_load_data_content(data, EXIF_IFD_1, d + 6, ds - 6, offset, 0);
    }
  }

  /*
   * If we got an EXIF_TAG_MAKER_NOTE, try to interpret it. Some
   * cameras use pointers in the maker note tag that point to the
   * space between IFDs. Here is the only place where we have access
   * to that data.
   */
  interpret_maker_note(data, d, fullds);

  /* Fixup tags if requested */
  if (data->priv->options & EXIF_DATA_OPTION_FOLLOW_SPECIFICATION) {
    exif_data_fix(data);
  }
}

void
exif_data_save_data(ExifData *data, unsigned char **d, unsigned int *ds)
{
  if (ds) {
    *ds = 0;  /* This means something went wrong */
  }

  if (!data || !d || !ds) {
    return;
  }

  /* Header */
  *ds = 14;
  *d = exif_data_alloc(data, *ds);
  if (!*d)  {
    *ds = 0;
    return;
  }
  memcpy(*d, ExifHeader, 6);

  /* Order (offset 6) */
  if (data->priv->order == EXIF_BYTE_ORDER_INTEL) {
    memcpy(*d + 6, "II", 2);
  } else {
    memcpy(*d + 6, "MM", 2);
  }

  /* Fixed value (2 bytes, offset 8) */
  exif_set_short(*d + 8, data->priv->order, 0x002a);

  /*
   * IFD 0 offset (4 bytes, offset 10).
   * We will start 8 bytes after the
   * EXIF header (2 bytes for order, another 2 for the test, and
   * 4 bytes for the IFD 0 offset make 8 bytes together).
   */
  exif_set_long(*d + 10, data->priv->order, 8);

  /* Now save IFD 0. IFD 1 will be saved automatically. */
  exif_log(data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
           "Saving IFDs...");
  exif_data_save_data_content(data, data->ifd[EXIF_IFD_0], d, ds,
                              *ds - 6);
  exif_log(data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
           "Saved %i byte(s) EXIF data.", *ds);
}

ExifData *
exif_data_new_from_file(const char *path)
{
  ExifData *edata;
  ExifLoader *loader;

  loader = exif_loader_new();
  exif_loader_write_file(loader, path);
  edata = exif_loader_get_data(loader);
  exif_loader_unref(loader);

  return (edata);
}

void
exif_data_ref(ExifData *data)
{
  if (!data) {
    return;
  }

  data->priv->ref_count++;
}

void
exif_data_unref(ExifData *data)
{
  if (!data) {
    return;
  }

  data->priv->ref_count--;
  if (!data->priv->ref_count) {
    exif_data_free(data);
  }
}

void
exif_data_free(ExifData *data)
{
  unsigned int i;
  ExifMem *mem = (data && data->priv) ? data->priv->mem : NULL;

  if (!data) {
    return;
  }

  for (i = 0; i < EXIF_IFD_COUNT; i++) {
    if (data->ifd[i]) {
      exif_content_unref(data->ifd[i]);
      data->ifd[i] = NULL;
    }
  }

  if (data->data) {
    exif_mem_free(mem, data->data);
    data->data = NULL;
  }

  if (data->priv) {
    if (data->priv->log) {
      exif_log_unref(data->priv->log);
      data->priv->log = NULL;
    }
    if (data->priv->md) {
      exif_mnote_data_unref(data->priv->md);
      data->priv->md = NULL;
    }
    exif_mem_free(mem, data->priv);
    exif_mem_free(mem, data);
  }

  exif_mem_unref(mem);
}

void
exif_data_dump(ExifData *data)
{
  unsigned int i;

  if (!data) {
    return;
  }

  for (i = 0; i < EXIF_IFD_COUNT; i++) {
    if (data->ifd[i] && data->ifd[i]->count) {
      printf("Dumping IFD '%s'...\n",
             exif_ifd_get_name(i));
      exif_content_dump(data->ifd[i], 0);
    }
  }

  if (data->data) {
    printf("%i byte(s) thumbnail data available.", data->size);
    if (data->size >= 4) {
      printf("0x%02x 0x%02x ... 0x%02x 0x%02x\n",
             data->data[0], data->data[1],
             data->data[data->size - 2],
             data->data[data->size - 1]);
    }
  }
}

ExifByteOrder
exif_data_get_byte_order(ExifData *data)
{
  if (!data) {
    return (0);
  }

  return (data->priv->order);
}

void
exif_data_foreach_content(ExifData *data, ExifDataForeachContentFunc func,
                          void *user_data)
{
  unsigned int i;

  if (!data || !func) {
    return;
  }

  for (i = 0; i < EXIF_IFD_COUNT; i++) {
    func(data->ifd[i], user_data);
  }
}

typedef struct _ByteOrderChangeData ByteOrderChangeData;
struct _ByteOrderChangeData {
  ExifByteOrder old, new;
};

static void
entry_set_byte_order(ExifEntry *e, void *data)
{
  ByteOrderChangeData *d = data;

  if (!e) {
    return;
  }

  exif_array_set_byte_order(e->format, e->data, e->components, d->old, d->new);
}

static void
content_set_byte_order(ExifContent *content, void *data)
{
  exif_content_foreach_entry(content, entry_set_byte_order, data);
}

void
exif_data_set_byte_order(ExifData *data, ExifByteOrder order)
{
  ByteOrderChangeData d;

  if (!data || (order == data->priv->order)) {
    return;
  }

  d.old = data->priv->order;
  d.new = order;
  exif_data_foreach_content(data, content_set_byte_order, &d);
  data->priv->order = order;
  if (data->priv->md) {
    exif_mnote_data_set_byte_order(data->priv->md, order);
  }
}

void
exif_data_log(ExifData *data, ExifLog *log)
{
  unsigned int i;

  if (!data || !data->priv) {
    return;
  }
  exif_log_unref(data->priv->log);
  data->priv->log = log;
  exif_log_ref(log);

  for (i = 0; i < EXIF_IFD_COUNT; i++) {
    exif_content_log(data->ifd[i], log);
  }
}

/* Used internally within libexif */
ExifLog *exif_data_get_log(ExifData *);
ExifLog *
exif_data_get_log(ExifData *data)
{
  if (!data || !data->priv) {
    return NULL;
  }
  return data->priv->log;
}

static const struct {
  ExifDataOption option;
  const char *name;
  const char *description;
} exif_data_option[] = {
  {
    EXIF_DATA_OPTION_IGNORE_UNKNOWN_TAGS, N_("Ignore unknown tags"),
    N_("Ignore unknown tags when loading EXIF data.")
  },
  {
    EXIF_DATA_OPTION_FOLLOW_SPECIFICATION, N_("Follow specification"),
    N_("Add, correct and remove entries to get EXIF data that follows "
    "the specification.")
  },
  {
    EXIF_DATA_OPTION_DONT_CHANGE_MAKER_NOTE, N_("Do not change maker note"),
    N_("When loading and resaving Exif data, save the maker note unmodified."
    " Be aware that the maker note can get corrupted.")
  },
  {0, NULL, NULL}
};

const char *
exif_data_option_get_name(ExifDataOption o)
{
  unsigned int i;

  for (i = 0; exif_data_option[i].name; i++)
    if (exif_data_option[i].option == o) {
      break;
    }
  return _(exif_data_option[i].name);
}

const char *
exif_data_option_get_description(ExifDataOption o)
{
  unsigned int i;

  for (i = 0; exif_data_option[i].description; i++)
    if (exif_data_option[i].option == o) {
      break;
    }
  return _(exif_data_option[i].description);
}

void
exif_data_set_option(ExifData *d, ExifDataOption o)
{
  if (!d) {
    return;
  }

  d->priv->options |= o;
}

void
exif_data_unset_option(ExifData *d, ExifDataOption o)
{
  if (!d) {
    return;
  }

  d->priv->options &= ~o;
}

static void
fix_func(ExifContent *c, void *UNUSED(data))
{
  switch (exif_content_get_ifd(c)) {
    case EXIF_IFD_1:
      if (c->parent->data) {
        exif_content_fix(c);
      } else if (c->count) {
        exif_log(c->parent->priv->log, EXIF_LOG_CODE_DEBUG, "exif-data",
                 "No thumbnail but entries on thumbnail. These entries have been "
                 "removed.");
        while (c->count) {
          unsigned int cnt = c->count;
          exif_content_remove_entry(c, c->entries[c->count - 1]);
          if (cnt == c->count) {
            /* safety net */
            exif_log(c->parent->priv->log, EXIF_LOG_CODE_DEBUG, "exif-data",
                     "failed to remove last entry from entries.");
            c->count--;
          }
        }
      }
      break;
    default:
      exif_content_fix(c);
  }
}

void
exif_data_fix(ExifData *d)
{
  exif_data_foreach_content(d, fix_func, NULL);
}

void
exif_data_set_data_type(ExifData *d, ExifDataType dt)
{
  if (!d || !d->priv) {
    return;
  }

  d->priv->data_type = dt;
}

ExifDataType
exif_data_get_data_type(ExifData *d)
{
  return (d && d->priv) ? d->priv->data_type : EXIF_DATA_TYPE_UNKNOWN;
}
